The present invention relates to a sinter crusher, comprising a crushing screen member and crushing roll member, each with spaced crushing elements extending therealong so arranged and spaced that the screen supports hot sinter on its crushing elements and, upon rotation, the crushing elements of the roll member pass between the crushing elements of the screen member to fragment the hot sinter supported on the screen member and force the fragments through the screen member. More particularly, this invention relates to the novel construction of said crushing members for effectively cooling them.
The hot sinter which is discharged by sintering machines is reduced in size by sinter crushers. Since the sinter still has a temperature of several hundred degrees, the working surfaces of the sinter crusher are subject to great stresses, wear relatively quickly and must therefore be changed quite often. Of course, the wear can be reduced by a highly heat-resistant and durable design of the working surfaces, for example by designing it with high-chromium steels or by added carbide coating, but even then there is still a very considerable wear experienced. Another possibility of reducing the wear is the cooling of the working surfaces of the sinter crusher.
From DT-AS No. 22 16 120 a sinter crusher is known on which cross-bearer of the crushing screen is on bearings at each end, with a hollow space as well as supply and withdrawal lines for the cooling medium. For simplification of the supply and withdrawal of the cooling medium to each cross-bearer the hollow cavity of each cross-bearer is separated into two chambers by means of a longitudinal divider wall, which at one end of the individual screen cross-bearer has the supply emptying into the one chamber and the removal taking place from the other chamber, and both chambers are connected to each other at the other end of the screen cross-bearer.
This configuration of the screen cross-members is also known from BE-PS No. 689 431. In addition, here too the shaft and the crushing spikes are hollow and are flushed with the cooling medium one after the other. The configuration of the screen cross-bearers is relatively expensive. In addition, there are large temperature differences in the cooling medium during the cooling process, unless a very large amount of cooling medium is fed through. This is true to an increased extent in the cooling of the crushing spikes, since these are flushed one after the other. Moreover, the cooling medium, as a result of the lower circuit resistance, flows principally through the shaft, so that the cooling of the crushing spikes is poor.
DT-AS No. 22 34 019 describes a cooling of the crushing spikes and the shaft in a manner so that the shaft is surrounded by a casing, and the hollow cavities of the crushing spikes are connected by the hollow cavity between the shaft and the casing, and in the hollow cavities of the crushing spikes separating walls are added for a directed circulation flow of the cooling medium to the sections which are radially the farthest away. The cooling medium flows through all the crushing spikes one after the other in succession. With this design, of course, the cooling medium is forced into the outermost parts of the crushing spikes, but for this, a rather expensive construction is necessary. In addition, there is no elimination of the great differences in the temperature of the cooling medium in the individual parts to be cooled.
The object of the present invention is the improvement of the cooling of sinter crushers and to keep the expenditures necessary for this purpose as low as possible.
The solution of this problem is achieved by means of the invention in that the crushing screen member is designed as a bracketed or multi-toothed screen. It consists of a hollow outer covering with hollow crushing teeth, and in the outer covering is located a supply line for the cooling medium with outlet openings in the form of nozzles in the hollow cavity of each individual crushing tooth, and the hollow space of each individual crushing tooth is connected with the hollow space of the outer covering by means of return openings for the heated cooling medium in the wall of the outer covering, and the outer covering is equipped with a drain. The working surfaces of the sinter crusher can be covered with carbide metals or can consist of carbide metals. The cooling medium can consist of water, whereby a spraying of water with cooling by evaporation is possible, or it can consist of air or an air-water mixture, of steam or other media with a good heat transfer property.
A significant improvement lies in the fact that the outer covering of the bracketed screen is designed as a tube. This achieves the best durability values at torsion loads.
A significant improvement lies in the fact that the outlet openings in the form of nozzles are located in the hollow spaces of the crushing teeth by means of extension pieces in the vicinity of the working surfaces of the crushing teeth to be cooled. This achieves an especially good cooling of the working surfaces, especially when the hollow space is completely filled with the cooling medium, since a strong turbulence of the flow at the working surfaces is produced. The direction of the flow of the cooling medium directly on the working surfaces is considerably improved as compared to outlet openings which end at about the level of the wall of the outer covering.
A significant improvement lies in the fact that the crushing roll member is designed as a hollow body, and in the crushing roll is located at least one supply line for the cooling medium with outlet openings in the form of nozzles in the hollow cavity of each individual crushing spike and the hollow space of each individual crushing spike is connected with the hollow space in the crushing roll through return openings for the heated cooling medium in the wall of the crushing roll, and the crushing roll is equipped with a drain. If only one feed line is used for the cooling medium, all of the nozzle outlet openings are connected with the supply lines by means of connecting tubes. With several supply lines the nozzle-type outlet openings can be connected with the appropriate supply line either directly or by means of short connecting lines. The cooling media to be considered are those described for the cooling of the crushing teeth.
A significant improvement consists in the fact that the crushing roll member is designed as a tube. This achieves the best durability values at torsion loads.
A significant improvement lies in the fact that the nozzle-type openings are located by means of extension pieces in the hollow cavities of the crushing teeth in the vicinity of the working surfaces of the crushing spikes to be cooled. This achieves an especially good cooling of the working surfaces, especially if the hollow space is completely filled with the cooling medium, since a strong turbulence of the flow is produced at the working surfaces. The direction of the flow of the cooling medium directly on the working surfaces is considerably improved as compared to outlet openings which end at about the level of the wall of the outer covering.